Maria often has walk with ___ parents in the morning.

Maria often has a walk with__parents in the morning.

A. she

B. her

C. their

听力原文：W: I wish Maria would put on a different record. She has played that song a thousand times.

M: At least. It used to be one of my favorites before I had to hear it so often.

Q: What did the man and woman think of Maria's record?

(13)

A．They're happy Maria's playing it again.

B．They are both very tired of it.

C．The man likes to listen to it often.

D．The woman has never heard it before.

第一篇 Putting Plants to Work

Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels(太阳能电池板) for decades. But plants are the real experts. They’ve been using sunlight as an energy source for billions of years.

Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide(二氧化碳), and water into sugars and starches(淀粉), stored energy that the plants can use. This conversion process is called

photosynthesis(光合作用). Unfortunately, unless you’re a plant, it’s difficult and expensive to convert sunlight into storable energy. That’s why scientists are taking a closer look at exactly how plants do it.

Some scientists are trying to get plants or biological cells that act like plants, to work as very small photosynthesis power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Colo., is working with green algae(水藻). She’s trying to trick them into producing hydrogen instead of sugars when they perform. photosynthesis. Once the researchers can get the algae working efficiently the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.

The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthesis, plants normally make sugars or starches. “But under certain conditions, a lot of algae are able to use the sunlight energy not to store starch, but to make hydrogen.” Ghirardi says. For example, algae will produce hydrogen in an airfree environment. It’s the oxygen in the air that prevents algae from making hydrogen most of the time.

Working in an airfree environment, however, is difficult. It’s not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate(硫酸盐) from the environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.

Unfortunately, removing the sulfate also makes the algae's cells work very slowly, and not much hydrogen is produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work, they may be able to speed the cells’ activity and produce larger quantities of hydrogen.

The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says, and they can grow almost anywhere: “You can grow them in a reactor, in a pond. You can grow them in the ocean. There’s a lot of flexibility in how you can use these organisms.”

31 How do plants relate to solar energy?

A They have been using it for billions of years.

B They are the real experts in producing it.

C They have been a source of it.

D They have been used to produce it.

请根据以下内容回答1-5题

Putting Plants to Work

Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels

for decades. But plants are the real experts: They've been using sunlight as an energy source for billions of years.

Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide, and water into sugars

and starches, stored energy that the plants can use. This conversion process is called photosynthesis. Unfortunately,

unless you're a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are

taking a closer look at exactly how plants do it.

Some scientists are trying to get plants, or biological cells that act like plants, to work as miniature photosynthetic

power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden, Colo.,

is working with green algae. She's trying to trick them into producing hydrogen instead of sugars when they

perform photosynthesis. Once the researchers can get the algae working efficiently, the hydrogen that they

produce could be used to power fuel cells in cars or to generate electricity.

The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthesis,

plants normally make sugars or starches. “But under certain conditions, a lot of algae are able to use the

sunlight energy not to store starch, but to make hydrogen.” Ghirardi says. For example, algae will produce

hydrogen in an airfree environment. It's the oxygen in the air that prevents algae from making hydrogen most

of the time. Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap

energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate from the

environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.

Unfortunately, removing the sulfate also makes the algae's cells work very slowly, and not much hydrogen is

produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae.

With more work, they may be able to speed the cells' activity and produce larger quantities of hydrogen.

The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and

to feed, Ghirardi says, and they can grow almost anywhere:

“You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in

how you can use these organisms. ”

What does the writer Say about plants concerning solar energy?_______

A Plants are the real experts in producing solar energy.

B Plants have been used to produce solar energy.

C Plants have been using solar energy for billions of years.

D Plants have been a source of solar energy.

The most suitable holiday for Peter and Maria would be ______, as it is cheap and sounds very interesting.

A．the summer holidays in Mallorca

B．the tours guided by a professor

C．the Kibbutz holiday in Israel

D．the tours arranged near to town of Castries

听力原文：M：Hey，do you know where Maria is? Professor Lee wants to talk with her at his office，you know，about the exam．

W：I'm not sure．

Q：What can we learn from the conversation?

(13)

A．Maria is in the library now.

B．Maria didn't pass the exam.

C．Maria is probably a college student.

D．The man wants to see Maria at his office.

The most suitable holiday for Peter and Maria would be ________,as it is cheap and sounds very interesting

[A] the summer holiday in Mallorca

[B] the tours guided by a professor

[C] the Kibbutz holiday in Israel

[D] the tours arranged near to town of Castries

Alloftheclientcomputersinyourcompany’snetworkareWindows2000portablecomputers.AusernamedMariastoresSalesfilesinherMyDocumentsfolder.Sheusesthesefileswhenshetravels.

Mariainformsyouthatwhenshetakesherportablecomputertotradeshows,shecanaccesssomeoftheSalesfilesbutnotallofthem.Whenherportablecomputerisconnectedtothenetworkattheoffice,shecanaccessallofthefiles.YouneedtoenableMariatoaccessallofthefilesinherMyDocumentsfolderwhensheisworkingremotely.

Whatshouldyoudo?（）